In recent years, electric vehicles that employ an electric motor as the driving source and also the so-called hybrid vehicles based on the combination of an electric motor as the driving source and another driving source (for example, an internal combustion engine, fuel cell, or the like) are adapted to practical use. In such vehicles, a battery to supply electricity qualified as the energy to the electric motor is loaded. For this battery, a secondary battery represented by a nickel-cadmium battery, a nickel-hydrogen battery, a lithium ion battery, or the like that can be charged and discharged repeatedly is used.
A secondary battery is constituted of a battery module in which battery cells are stacked. This battery module is loaded in a vehicle in a stored state in a battery case. This battery case and the battery module together with other internal components stored in the battery case are referred to as a battery pack. Cooling apparatuses such as a fan, duct, and the like are attached to the battery pack in order to introduce cooling airflow into the interior for controlling the temperature of the battery module stored inside.
During the past several years, there is a demand for a secondary battery of larger capacitance. To meet this demand, a possible arrangement of the battery pack is inside the center console box located between the driver seat and the front passenger seat for a large-sized car, as an example of the site where the secondary battery is to be loaded. In a hybrid electric vehicle and the like, the motor qualified as the driving source is incorporated in the engine room located at the front of the vehicle. Electric power must be supplied to this motor from the battery pack by means of the power cable. A long route of the power cable must be avoided in view of the passage of high voltage and high-amperage current. Arrangement at the center console box is advantageous from the standpoint of rendering the power cable length short due to the location close to the engine room. Furthermore, by placing the battery pack between the driver seat and the front passenger seat, a larger room for the passenger compartment can be provided effectively. Thus, the arrangement of the battery pack in the center console box between the driver seat and the front passenger seat can be thought of as an appropriate location, as mentioned above.
In view of the limited space in the center console box located between the driver seat and the front passenger seat, the battery pack, the cooling apparatuses, and other peripheral equipment must be disposed between and in the proximity of the driver seat and the front passenger seat without degrading the environment of interior comfort in the vehicle. Further, the effect of outside temperature on the battery pack must be considered. In addition, the workability in assembling the battery pack, cooling apparatus, and other peripheral equipment into the center console box must be taken into account.
Japanese Patent Laying-Open No. 2004-237803 discloses a structure in which the battery pack is arranged below the seat, and the airflow subsequent to cooling the battery pack is forced in the vehicle widthwise direction. However, there is a problem when a battery of large capacitance is to be loaded in the vehicle. A large battery pack cannot be placed under the seat since the space is insufficient. Further, the large amount of air to cool the battery pack may cause discomfort to the passenger if the cooling air subsequent to the cooling operation is simply output from one place (in the vehicle), leading to degradation in the in-car environment.
Japanese Patent Laying-Open No. 2001-105893 discloses a structure of loading the battery pack between the driver seat and the front passenger seat (FIG. 5). However, this publication is silent about the specific structure of disposing the cooling apparatus to cool the battery pack and other peripheral equipment.
Japanese Patent Laying-Open No. 2004-296217 discloses (in Paragraph 0011) two sets of battery packs, each battery pack provided with a cooling fan. The passage resistance of the coolant at each battery pack is designed such that the flow of coolant in each battery pack is substantially equal. However, the publication is silent about the problem of the in-car environment being degraded due to the airflow subsequent to cooling.
Japanese Patent Laying-Open No. 2004-268779 discloses a battery pack arranged below and traversing the front seat. However, there is a possibility that the battery pack output may be adversely affected since the region below the front seat is readily influenced by the heat from the exhaust pipe located under the floor of the vehicle.
Japanese Patent Laying-Open No. 2002-219949 discloses a cooling structure of drawing in cooling air from below the battery pack to conduct a cooling airflow upwards. This publication teaches that the battery pack is loaded at the trunk at the rear of the vehicle, and is absolutely silent about the approach of loading the battery pack in the passenger compartment.
Japanese Patent Laying-Open Nos. 2004-268779 and 2004-255892 disclose an inverter arranged in the center console box. It is difficult to ensure space to pass the harness through for the electrical connection between the battery pack located under the front seat and the inverter. There is a possibility of degradation in the workability of assembling respective apparatuses.